Mechanical induction with a Foley catheter is a frequent used method for induction of labor. Concerns have been raised on whether the mechanical aspect of this procedure can cause damage to the cervix and increase the risk of preterm birth (PTB) in a subsequent pregnancy. Here, we compare PTB rates (before 37 weeks of gestation) in subsequent pregnancies in women randomised to induction of labor with a Foley catheter versus Prostaglandins (PGE).
We performed a follow study of two multicentre randomised controlled trials (PROBAAT 1 and 2). In these trials, women with a singleton pregnancy at term in cephalic position with an indication for labor induction were randomised to either a 30c Foley catheter or PGE (vaginal PGE2 in PROBAAT 1 or oral PGE1 in PROBAAT 2). There were 10 hospitals who agreed to participate in the follow up study. We collected data on subsequent pregnancies, including their outcome, from hospital charts.
Of the 852 eligible women (414 in PROBAAT 1 and 438 in PROBAAT 1), 98 were lost to follow up (10% in each group). Of the 394 woman randomised to a Foley catheter, 199 women (51%) had a subsequent pregnancy beyond 16 weeks of gestation, versus 193 women (52%) among the 370 women who received PGE. There were no differences in baseline characteristics. The PTB-rate was 8/199 (4.0%) in the Foley induction group versus 7/193 (3.6%) in the prostaglandin group, respectively (RR 1.11; 95%CI 0.41–3.0). After excluding women with a multiple pregnancy (n=6) and an iatrogenic PTB (n=3), spontaneous PTB rates were 1.6% versus 1.6%, respectively (RR 0.97; 95%CI 0.25-3.82).
In women with a singleton pregnancy at term, induction of labour with a Foley catheter does not increase the risk of spontaneous PTB in a subsequent pregnancy as compared to induction of labor with Prostaglandins.
© 2018 Published by Elsevier Inc.